Niagara/Grimsby

I drove up it once - it's steep but about mid-way there seems to be a bit of rest - then it climbs again.  Might be an idea to practice it a couple of times if you can beforehand.  I'm sure there are oodles of folks on here that can describe it better from a cycling perspective.

That pretty much sums it up, except that "mid-way rest" is still at a 4-5% incline, but compared to the rest of the hill, it does look flat.

It's a great idea to do a few practice runs up the hill (Park Hill) if possible. That would make you confident. I know I'd probably c*%p if I saw it for the first time in the middle of a race! The first incline is the worst part as you can't get a run at it and all of a sudden you're going straight up. It is challenging, but very do-able. I finally climbed it last summer. Coming down is exciting. Fastest I've ever gone on 2 wheels!!

I drove the course today to see what it was like. That hill looks fun

You will definitely go slower during the second climb but it's shorter than the first climb.  You can get some momentum for the first climb but it won't really do you much as you'll have to get out of your seat unless you have a MTB cassette.  It's a mild uphill for a km starting from underneath the highway to the base of the hill so keep that in mind.

I wouldn't blast out of T1 as I would save it for the climb and there are a few mild rollers up top of the escarpment.  I wouldn't worry about those too much... the challenge is the head wind up there.